Create an internal class for InputMethodConfiguration.

This class easily enables to manage the lifetime of objects which are used with InputMethodManager.  I will make a class for Accessibility and this class manages the Accessibility class.

BUG=271228

Review URL: https://codereview.chromium.org/80633002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237050 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237050